To provide a thermal-transfer sheet having a back layer that can be prepared without heat treatment such as aging and is superior in heat resistance and sliding property, and has no such defect of printed images as wrinkling and tailing during printing. A thermal-transfer sheet having a substrate film, a transfer ink layer formed on one face thereof, and a back layer formed on the other face thereof, the back layer comprising: a binder containing a polyamide-imide resin (A) having a Tg of 200.degree. C. or higher and a polyamide-imide silicone resin (B) having a Tg of 200.degree. C. or higher, as determined by differential thermal analysis, a mixture of a polyvalent metal salt (C) of alkylphosphoric ester and a metal salt (D) of alkylcarboxylic acid, a silicone oil (E), and an inorganic filler (F) containing fine particles (F1) of an inorganic material having a Mohs' hardness of 3 or less alone or a mixture of fine particles (F1) of an inorganic material and fine particles (F2) of an inorganic material having a Mohs' hardness of more than 3, the metal salts (C) and (D) having an average particle size of 5 .mu.m to 20 .mu.m and the inorganic filler (F) having an average particle size of 0.05 to 5.5 .mu.m.